It is often necessary or desirable to transport or maintain a small quantity of aquatic life in a small container. For example, the use of live bait, such as minnows or shrimp, for fishing requires that a container be used to transport a sufficient amount of bait for a day long fishing trip. It is preferred that the container provide sufficient aeration and fresh water for the bait during this period. Another example is the collection of live marine animals, such as crabs or shrimp, for personal consumption or resale to distributors or restaurants. It is most desirable to transport and maintain shrimp or other marine life in a container that provides sufficient oxygen and fresh water for the marine life to stay alive and well until just before consumption.
Typically, a container is filled with water and aerated with a device such as a bubble tube. When using a small fishing or shrimping boat, the container may take the form of a common cooler or refrigeration box, comprising a plastic shell with a hinged lid. These coolers vary in size, but typically a water-filled cooler may be moved by one or two individuals from a boat to the dock and into an automobile. Furthermore, in commercial shrimping or fishing operations, the container for storing marine life may be significantly larger and perhaps comprise a portion of the vessel's hull. Certainly, the capacity of the oxygenating device will vary in proportion to the size of the container and the population of marine life to be maintained. If the population of marine life maintained in the container is high relative to the size of the container and the amount of water contained therein, then it is necessary to periodically replace the water with fresh water due to the increase in the concentration of waste products. The operation of removing and replacing the water may be accomplished through a number of methods. With small containers or coolers, this operation may include manually bailing water with a bucket or tipping the container over the side of the boat. Both of these methods, and other similar methods, are inefficient and require hard work. Furthermore, these methods involve a risk that some or all of the marine life will be swept from the container along with the water or otherwise lost during the operation.
For larger aqua-culture environments, such as ponds, tanks or other aquatic containment systems used for raising and maintaining fish or other aquatic livestock, aeration is also needed to supply sufficient oxygen to the aquatic livestock or the livestock may die. In addition to the aeration apparatus, the aquatic environment needs agitation of the bottom surface to prevent stagnation of the bottom portion of the aquatic environment. Stagnation at the bottom of the aquatic environment leads to undesirable growth of bacteria and/or fungus in the aquatic environment which is detrimental to the health of the aquatic livestock. Agitation of the bottom of the aquatic environment also stirs up and redistributes the nutrients or food that have sunk to the bottom of the aquatic environment.
Various aerators have been used to provide oxygenation to various aquatic environments. For example, U.S. Pat. No.'s 5,275,762 and 5,213,718, hereby incorporated by reference, disclose a floating aerator that is useful for aerating a top portion of an aquatic environment. These patents also disclose an alternative embodiment that is fixedly attached to a bottom of the aquatic environment to provide aeration to the bottom portion of the aquatic environment. However, typical aerators are not capable of providing aeration at various vertical positions within the aquatic environment, as well as agitation to the bottom of the aquatic environment. Furthermore, these aerators do not provide a scheme for controlling circulation within the aquatic environment.
In addition to the above aeration and replenishment needs, typical aerators use air having an ambient temperature. In most instances, aquatic life fares better at certain temperatures native to their environment. Thus, even aerated water at a less than an optimum temperature may adversely influence the lifespan, health, reproduction, and growth of aquatic life. Furthermore, since most sport fishing, using live bait, is done during the time of year when the ambient temperature is higher than the desired water temperature, by using air with an ambient temperature to aerate a container of bait, the water temperature may actually rise and accelerate the problems for aquatic health.
Therefore, there remains a need for an apparatus that aerates the aquatic environment with non-ambient temperature air. It would be desirable for the apparatus to aerate the aquatic environment at various vertical positions. There is also a need for a method for maintaining oxygenation, providing bottom agitation and controlling circulation to an environment for aquatic livestock.